Kenbo

Kenbo

Active Member
I've a rusty 1997 Tdi automatic for farm use. It lives in a shed and comes out a couple of times annually.
Earlier in the week I put a good battery in it and we used it all day, stop start, repairing fences. Next day it started well as usual but later on starter turned it fine but it wouldn't fire up. I phoned around and was advised to change the lift pump but it made no difference. On checking closer, fuel is getting to the injector pump but not to the injectors. I then removed the plunger at the stop solenoid, no effect and I checked, diesel getting to that switch also.
I went online, this site and others, lots of different advices but people rarely reported back on the end results.
The module at the top of the pump, can I check anything there? It was suggested that I need to contact a main dealer for some unique immobilizer code? Can I check an ecu beside the accelerator and if so what does it look like? I'd greatly appreciate some help, this Disco's been very useful to us for many years. IMG_20200411_110828.jpg IMG_20200411_110945.jpg
 
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Does no 4 injector have a wire going to it this injector tells the injectors to fire engine check light?.
 
Kenbo said:
Yes, wire from No 4, can I test anything there?
Click to expand...
Bump..... I spent this morning searching online, lots of conflicting advice.
Is an immobilizer fault likely as the engine spins over yet no diesel? Where are the ecus located?
 
Kenbo said:
Bump..... I spent this morning searching online, lots of conflicting advice.
Is an immobilizer fault likely as the engine spins over yet no diesel? Where are the ecus located?
Click to expand...

Engine ecu is behind the panel to the right of the throttle pedal, real tight access iirc
Google spider immobiliser relay, now sure if it applies to the edc models, but got to be worth a read up?
The spider widget thing is behind the ehater contol panels, and Iirc can be bypassed.

Worst comes to the worst you can fit a std injector pump and throttle pedal.
 
Forgot to say, again from memory with ign on but not cranking, you should be able to hear the injection pump ticking.
Also the inejction pump has a multi plug quite close, also worth a look for corrosion etc.
Battery volts good?

Sadly even when they were current, there was not a wealth of info/experience out there, and now they are over 20 yrs old.
 
Thanks, no spider as it's a later auto with EDC. Good cranking speed, no issues there. When ign is on there's a buzzing noise ok, I didn't realize it was the pump.
The body's severely corroded and I originally bought it for off road farm use so I'll spend time but not worth spending a lot of money on it.
Will have a look at the links, thanks so far.
 
Kenbo said:
Thanks, no spider as it's a later auto with EDC. Good cranking speed, no issues there. When ign is on there's a buzzing noise ok, I didn't realize it was the pump.
The body's severely corroded and I originally bought it for off road farm use so I'll spend time but not worth spending a lot of money on it.
Will have a look at the links, thanks so far.
Click to expand...

Used standard inj pumps 100/200 quid, and of course the pedal/cable assy.
On the upside the inj pump and the engine will always be worth money.

I have no idea where the crank sensor is located? but if the ecu cannot see the engine turning over, it will not give any fuel, thinking rats/mice on the wiring?
 
lynall said:
Used standard inj pumps 100/200 quid, and of course the pedal/cable assy.
On the upside the inj pump and the engine will always be worth money.

I have no idea where the crank sensor is located? but if the ecu cannot see the engine turning over, it will not give any fuel, thinking rats/mice on the wiring?
Click to expand...
I'm going to have a closer look in a few days, it's stored 15 miles away so I'll take plenty of tools and a multimeter.
Thanks.
 
I spoke to a specialist this morning, he told me to check the red light on the dash if it's on when cranking the engine, shouldn't be. He also mentioned No 4 injector and to check the wiring to it.
I also have a very nice TDI auto in my garage same set up and was trying to remove the black box/plug at the top of the pump to see what's behind. I've got all the screws out, it's moving but is it ok to force it a bit? I certainly don't want to disable this one as well.
 
Kenbo said:
I also have a very nice TDI auto in my garage same set up and was trying to remove the black box/plug at the top of the pump to see what's behind. I've got all the screws out, it's moving but is it ok to force it a bit? I certainly don't want to disable this one as well.
Click to expand...

the black box you refer to is 'hardwired' into the pump, nothing to see behind it except metal 'wire' traces going to electrical components inside the top of the pump.
hopefully it wont leak after you bolt it back ono_O

Rich.
 
Zed. said:
the black box you refer to is 'hardwired' into the pump, nothing to see behind it except metal 'wire' traces going to electrical components inside the top of the pump.
hopefully it wont leak after you bolt it back ono_O

Rich.
Click to expand...
Thanks Rich, from old posts I was expecting a few wires, certainly wasn't expecting diesei, yes a bit worried about a leak. I'm starting to realise that a lot of what I've been reading online is rubbish.
 
Back again, I disconnected the wire from no 4 injector on my "good" disco to check resistance etc on a working engine. I was surprised to find that it started and ran well with this injector wire disconnected.
I thought it couldn't run without this?
 
Kenbo said:
Back again, I disconnected the wire from no 4 injector on my "good" disco to check resistance etc on a working engine. I was surprised to find that it started and ran well with this injector wire disconnected.
I thought it couldn't run without this?
Click to expand...

According to that link I posted earlier, if the engine ecu loses any feedback from any of the sensors, it uses a default value so the engine can still run?
That was why I said check crank sensor, as it will still need to know the engine is rotating to fire up.
As you have two, a quick test would be to unplug the crank sensor on the good car and see what happens?

Iirc the inj with sensor is NLA.
 
Thanks, I'd like to check it out even for my own interests but haven't had a chance to look at it yet. From what I read, if it needs changing its a difficult job.
Another thought, I spent all yesterday evening online and found a couple of posts with exactly the same fault where a change of ecu was the answer. It's unclear if the alarm module was affected or which remote fob was used. These could be swopped from my good auto without risk. Any advice on this?
Ken.
 
Atm I would be wary of possibly disabling both cars!
Maybe look for a 2nd hand ecu, they must be worth sod all?
 
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Well, I left my good Disco alone apart from checking connections and resistances on the crank sensor and 4th injector. Went out to the farm with all this info to compare. Churned the engine over to check for the red warning dash light, it was off, but I noticed a spurt of diesel out of one of the loose injector unions. I bled the rest and it started!
Where do I go now? Was it an immobilizer glitch, any way to avoid a repeat?
 
Back to the start again, used the Disco again but it only worked properly for a few hours and then failed as before

I read somewhere that it was possible to bridge pins 11& 12 on the immobilizer, the green ecu behind the glove compartment.
I've taken it home to inspect, anyone know, how are the pins numbered?
 

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